3.2.1.2 Prokaryotes and Viruses

Question 1

What are prokaryotic cells commonly referred to as?

Answer 1

Bacteria

Question 2

List three key differences between prokaryotic and eukaryotic cells.

Answer 2

• Much smaller
• No membrane-bound organelles
• A single circular chromosome

Question 3

What type of chromosome do prokaryotic cells have?

Answer 3

A single circular chromosome

Question 4

What is the composition of prokaryotic DNA?

Answer 4

DNA is not associated with proteins

Question 5

What are the essential components found in all prokaryotic cells?

Answer 5

• Cytoplasm
• Cell membrane
• Ribosomes (70S)
• Single circular DNA molecule in cytoplasm
• Cell wall made of murein (glycoprotein)

Question 6

What additional structures may be found in many prokaryotic cells?

Answer 6

• One or more plasmids
• Capsule surrounding cell
• One or more flagella

Question 7

True or False: Viruses are considered living organisms.

Answer 7

False

Question 8

What are the three essential components that all viruses possess?

Answer 8

• Genetic material (DNA, RNA, or ssDNA)
• A protein capsid
• Attachment proteins

Question 9

What type of proteins may be part of a virus’ structure?

Answer 9

• Attachment proteins
• Enzymes within the matrix (e.g., reverse transcriptase)

Question 10

Fill in the blank: Viruses may have a _______ envelope.

Answer 10

lipid

Question 11

Give 3 similarities between human DNA and prokaryote’s DNA

Answer 11

• nucleotide structure is identical
• nucleotides are joined together by phosphodiester bonds
• DNA in mitochondria/ chloroplasts is similar to DNA in prokaryotes

Question 12

Give 4 differences between human and prokaryote’s DNA

Answer 12

• human DNA is longer
• human DNA contains introns, whereas prokaryotic DNA does not
• human DNA is linear, whereas prokaryotic DNA is circular
• human DNA is associated with histones, whereas prokaryotic DNA is not

Question 13

How do prokaryote cells divide?

Answer 13

binary fission

Question 14

5 steps of binary fission

Answer 14

1. Circular DNA replicates (both copies attach to cell membrane)
2. Plasmids replicate
3. Cell membrane grows between DNA molecules and pinches inwards, dividing cytoplasm in 2
4. New cell wall forms between 2 DNA molecules
5. New cells formed are identical daughter cells

Question 15

What are the properties of the resulting daughter cells formed after binary fission?

Answer 15

identical daughter cells
- same copy of circular DNA
- variable number of plasmids